Research project SR/11/153 (Research action SR)
Context and objectives
Kruger National Park (KNP) and its surroundings are considered an area with a homogenous risk for foot-and-mouth disease (FMD) transmission between buffaloes and cattle. Stratification of this risk however, would allow prioritizing areas for vaccination and fence maintenance and a better allocation of resources. GRAZEO is a spin-off of the EPISTIS (SR/00/102) project where several models were developed for this purpose at different scales, using remote sensing and spatial modelling. In GRAZEO however, the emphasis will be put on the role of the natural vegetation as a key factor of habitat suitability (grazing suitability) for large herbivores.
The abundance and quality of the forage source is known to be a key driver of feeding patterns and distribution of livestock and wild grazers in savannah rangelands.
Therefore, the main aim of GRAZEO is to explore the potential of the new generation of very-high spatial and spectral resolution sensors, such as WorldView-2, for (i) developing methodologies for mapping grass patches, grass biomass and quality indicator (nitrogen concentration), as well as tree species communities as complementary forage quality indicator, at a scale compatible with savannah spatial heterogeneity and animal movements; (ii) Investigating how these improved inputs, along with adapted modelling processes and multiple scenarios testing can contribute to improving the buffalo-cattle contact modelling outputs.
Methodology
As a first step all relevant existing data will be collected/acquired, prepared, organized and made available. Additionally, 3 WorldView-2 images will be acquired during the wet, transition and dry season. These images will be preprocessed, and serve as a basis to extract grass, tree and bare soil layers using object-based image analysis (OBIA). Next, this derived tree layer will constitute the base for developing and assessing a multi-temporal framework to map tree species at single crown level. The grass layer will be used to assess the usefulness of the red-edge band to produce regional scale maps of grass biomass and nitrogen concentration. As a last step, both detailed tree species information and grass biomass and nutrient concentration will be used to improve fine-scale buffalo-cattle contact risk models, based on the Bayesian and GIS-based models developed in EPISTIS. Each of these objectives requires different types of input data, which will be collected during multiple field missions.
Results expected
- Techniques for separating tree cover, grass cover, and bare ground from VHR panchromatic and multispectral imagery combined with OBIA.
- Producing regional scale map of grass biomass and nitrogen concentration using red-edge band.
- Improve the mapping of tree species at single crown scale, and associated vegetation communities by assessing a multi-temporal framework of VHR and band-rich multispectral visible-NIR satellite imagery to.
- Improve the modelling and mapping of the risks of contact between cattle and buffaloes
- Deliver new inputs, such as refined indicators of pressure on the fence, for modeling and mapping of the risks of contact between cattle and buffaloes.
